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Complete
MCP23S17.cpp
- Committer:
- mikeb
- Date:
- 2016-01-30
- Revision:
- 3:ecfa4fa0b5a7
- Parent:
- 0:8f5b2af5e1d5
File content as of revision 3:ecfa4fa0b5a7:
/* MCP23S17 - drive the Microchip MCP23S17 16-bit Port Extender using SPI * Copyright (c) 2010 Romilly Cocking * Released under the MIT License: http://mbed.org/license/mit * * version 0.4 */ #include "mbed.h" #include "MCP23S17.h" MCP23S17::MCP23S17(SPI& spi, PinName ncs, char writeOpcode) : _spi(spi), _ncs(ncs) { _writeOpcode = writeOpcode; _readOpcode = _writeOpcode | 1; // low order bit = 1 for read _init(); } char MCP23S17::_read(char address) { _ncs = 0; _spi.write(_readOpcode); _spi.write(address); char result = _spi.write(0); _ncs = 1; return result; } char MCP23S17::_read(Port port, char address) { return _read(address + (char) port); } void MCP23S17::_write(char address, char data) { _ncs = 0; _spi.write(_writeOpcode); _spi.write(address); _spi.write(data); _ncs = 1; } void MCP23S17::_write(Port port, char address, char data) { _write(address + (char) port, data); } void MCP23S17::_init() { _write(IOCON, (IOCON_BYTE_MODE | IOCON_HAEN )); // Hardware addressing on, operations toggle between A and B registers } void MCP23S17::direction(Port port, char direction) { _write(port, IODIRA, direction); } void MCP23S17::configurePullUps(Port port, char offOrOn) { _write(port, GPPUA, offOrOn); } void MCP23S17::interruptEnable(Port port, char interruptsEnabledMask) { _write(port, GPINTENA, interruptsEnabledMask); } void MCP23S17::mirrorInterrupts(bool mirror) { char iocon = _read(IOCON); if (mirror) { iocon = iocon | INTERRUPT_MIRROR_BIT; } else { iocon = iocon & ~INTERRUPT_MIRROR_BIT; } _write(IOCON, iocon); } void MCP23S17::interruptPolarity(Polarity polarity) { char iocon = _read(IOCON); if (polarity == ACTIVE_LOW) { iocon = iocon & ~INTERRUPT_POLARITY_BIT; } else { iocon = iocon | INTERRUPT_POLARITY_BIT; } _write(IOCON, iocon); } void MCP23S17::defaultValue(Port port, char valuesToCompare) { _write(port, DEFVALA, valuesToCompare); } void MCP23S17::interruptControl(Port port, char interruptContolBits) { _write(port, INTCONA, interruptContolBits); } void MCP23S17::write(Port port, char byte) { _write(port, OLATA, byte); } char MCP23S17::read(Port port) { return _read(port, GPIOA); }